As a reminder, any registered Starbucks card can earn rewards under the MyStarbucksRewards program. In the U.S., it is estimated that about 25% of all transactions are with a registered card, and that there are more than four million active card holders. And in the past year, about 20 million transactions were with the mobile card phone application. That’s a lot of Starbucks cards in use! Given the massive numbers of customers using a registered card (or a registered card on their mobile device with the Starbucks app), understanding these rewards is more important now than ever before. And, there’s no doubt that Starbucks gains a lot of brand loyalty by having so many people carrying around their cards.